Controlling Scale on Citrus Trees 2


Our lemon tree is bursting into bloom with the warmer weather

Our lemon tree is bursting into bloom with the warmer weather

We’ve got a lemon tree growing in a large pot at the back doorstep. It’s just bursting in to bloom at the moment. Unfortunately we’re also starting to get a bit of scale appearing on the undersides of some of the leaves.

Scale are usually located on the underside of leaves and sometimes the stems of plants

Scale are usually located on the underside of leaves and sometimes the stems of plants

If you’ve got scale on your citrus trees, you’ll probably also notice that there are ants crawling over your tree too. Scales shoot a sweet substance called honeydew. Ants like to ‘farm’ the scale to feed on the honeydew. They’ll even pick the scale up and move them all over the tree. Honeydew also leads to sooty mould, a black dusty fungus that grows over the leaves and stems. Controlling the scale will also get rid of the sooty mould.

Scale insects secret honeydew which in turn attracts ants

Scale insects secret honeydew which in turn attracts ants

Scale in large numbers can cause leaf yellowing, leaf drop and die-back. Don’t worry though, it’s easily treated with a spray of white oil, which suffocates them. The great news is that it’s easy to make your own white oil to treat scale and aphids.

We've got a Meyer Lemon tree in a container at the back doorstep

We’ve got a Meyer Lemon tree in a container at the back doorstep

 


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2 thoughts on “Controlling Scale on Citrus Trees

  • Mike

    Hi there,
    I have 20 lemon trees but only 3 trees affected with scale. I have mixed a solution of cooking oil plus dishwashing liquid and add it to water, but it doesn’t seem to have much affect (like killing them). I get out there and scape the scale off the trees, but I want to know where they come from originally.
    Do they fly on the trees, or come from the soil. Is there a bug that lays eggs & begin the scale.
    It’s a big problem and I want the source rather than the cure.
    Thank you
    Mike

    • Leaf, Root & Fruit Post author

      Hi Mike,

      Scale seems to affect trees that are underfed and/ or have poor airflow. Is it continuously the same three trees that are affected with scale and the other 17 remain unaffected? If so that’s the clue to working out how to prevent it. What do those 3 trees have (or not have) that the other 17 don’t (or do)?

      Good Luck & Happy Gardening!

      Duncan